Generator or...??

[wesome]

Hoping someone can give me advice on my 1973 IH Cub discharging. The previous owner was fairly sure the battery cables were crossed. (It wouldn't have been difficult as both cables were red and one had black painted on the end). The "all red" one was grounded to a bolt under the seat. The ammeter doesn't seem to move regardless of what I do, so I suspect it's gone. I put in a new regulator and polarized the generator but I'm still getting discharge. I checked the battery with a meter- positive to neg posts and get a 12.86 V reading. When the tractor is started, voltage drops to 12.7V. Anything else I should check before forking out a bunch of money for a generator? Please be gentle- I'm both a newbie AND cheap

[tst]

color of the cables may not mean much, important part is that is a 12 volt Negative ground system, follow the chart to diagnose

[Glen]

Hi,
After checking it with the flow chart, you could check the generator's condition inside, instead of buying another generator.
The brushes, bearing in the front end, and bushing in the rear end might need replacing.

Below is a page from the Cub parts manual showing the generator a 1973 Cub would originally have.

http://www.farmallcub.info/manuals/cub_ ... 008-07.jpg

http://www.farmallcub.info/manuals/cub_ ... 008-08.jpg

I don't know if you have repaired a gen before. The brushes are number 6 in the pic, they wear down from use. When they wear down to small, the gen won't work anymore. Then they need replacing.
They may be worn down and need replacing, could be why the gen does not work, I don't know without seeing it.
You could look in the rear end of the gen with a light and see if the brushes are good, or wornout.

The brushes are held against the commutator by springs, when the gen is taken apart, the spring pressure is released, and the brushes fall out of place, they have to be pushed back again to put the gen together.
The bolts number 34 in the pic hold the gen together, the heads are on the rear end of the gen.
They are sometimes stuck, work them both directions if stuck, and be careful to not twist them off.

Don't try to turn the big screws on the sides of the gen, they are probably tight, and don't hold the gen together.
The gens are an open design, for cooling, this lets dirt in them, it might be dirty inside and need cleaning.
The commutator the brushes run on might be dirty and need cleaning. It should be shiny brass colored. They need sanding with fine sandpaper if dirty or rough.

If there are marks on the big part of the armature, number 40 in the parts pic, from rubbing on the magnets in the gen, the bushing and bearing in the ends of the gen need replacing.
The armature should not rub on the magnets.

The wiring needs to be good, and all the wire ends clean. Dirty wire ends and connections are sort of common on Cubs. Remove 1 wire end at a time, and sand the ends and the connections to clean them. Wipe off all sanding with a clean rag. Good luck.

[wesome]

I asked about the ground and the gent I bought it from indicated it was a negative ground.

[wesome]

That's a lot of info, Glen. Thank you. I'll check out the pics and re-read though I suspect it's beyond my intellectual capacity. Appreciate your response, sir.

[Glen]

Hi,
Below is the 1965 Cub owner's manual. The experts on here recommend people read it. It has lots of info about operation, maintenance, and lubrication. There is a table of contents on page 1. It shows how Cubs originally looked.
This is almost the same as a 1973 Cub manual would be. They don't have every year of manual on here. They have said on here that IH didn't make a new manual every year.

There is electrical system info in it.
IH changed Cubs to a 12 volt, negative ground system in 1964. The manual has 6 and 12 volt info, disregard the 6 volt info.
I would check or change all the oils before using the Cub. Low oil in a gear case can damage the parts in it. The lube section begins on page 59.
The transmissions commonly get water in them, from rain, or condensation over time.
The 2 final drive oils are separate from the trans, and need checking.
Changing the trans and final drive oils are on page 70.

http://farmallcub.com/rudi_cub/www.clea ... index.html

[wesome]

Excellent Glen. My thanks to you again! This will be very helpful.